I am running a sandbox game for a group of players who are used to more traditional campaigns. While my players all said they were on board with the open world, set your own goals, total freedom, and realistic consequences a sandbox implies, that claim hasn't yet been tested.

The PCs are gearing up to assassinate the commander of an enemy army. They've hatched a plan that involves splitting the party; all four of them will perform an interlocking piece of a larger plan. If anything goes wrong anywhere, the entire plan falls apart.

The plan is fairly brittle to begin with, and involves on the enemy reacting in the way they expect, when they haven't studied the enemy at all to know what to expect. Even worse, I know (but they don't) that there was a spy present at the meeting where the plan was hatched and discussed. The spy hasn't made its report yet when the last session adjourned, but will have ample opportunity to do so unless the players realize that there might have been a spy and start investigating (in which case it will probably be caught immediately).

If I stick to the sandbox GMing advice I've read before and simply portray the world as it is, this will be a TPK. The commander they're looking to assassinate is intelligent enough to target the most vulnerable points in the plan, and has enough force at his disposal to guarantee victory.

My players expect freedom to act how they like within the game world; they'll resent it if I try out-of-character to convince them to change course - this is a sandbox game, after all. I'm willing to retcon the spy away if I have to, but they're used to surprises and will notice (and be bored) if everything just goes according to plan.

How can I salvage this situation and not kill my PCs?

I have an intuition that killing PCs in this situation is bad, but I'm having trouble rationalizing it. Realistic consequences are part of the buy-in for a sandbox game. Is my intuition correct? If not, what is it about this situation that makes character death unfair?

\$\begingroup\$Remember that answers should be from experience. No matter how much you think experience from a different style of campaign should apply, answers without experience with TPKs and information-management in a sandbox game where un-dramatic, senseless death is possible are not actually going to be helpful.\$\endgroup\$
– SevenSidedDieJun 16 '15 at 15:19

4

\$\begingroup\$I voted to close this question because, as it stands, the question of whether or not to save your PC's can only be opinion-based. There's a good deal of other not primarily opinion-based approaches to this situation, such as Dale M's answer, but that's a frame challenge to an opinion-based question.\$\endgroup\$
– WrongOnTheInternetJun 16 '15 at 23:35

\$\begingroup\$I am impressed by many of the answers below. Just sayin'\$\endgroup\$
– Tony EnnisJun 20 '15 at 13:29

\$\begingroup\$Taking this answer as this is the course of action I'm planning to take, though the more philosophical answers better explain the reasoning for why to do this.\$\endgroup\$
– Tim CJun 17 '15 at 6:52

9

\$\begingroup\$Have the spy report his findings to the enemy commander and have the enemy commander react in a way that changes his daily routine in a noticeable way to the players.\$\endgroup\$
– Pieter BJun 18 '15 at 12:22

5

\$\begingroup\$@PieterB that one isn't bad: players make stupid mistakes, and so should NPCs. The spy could even be the one that makes a mistake -- the message from the spy is sent to the general through the usual channels, but it is damaged en-route. Now the general only has partial, flawed information about the plot, so doesn't react the way the "smart general" should (ie, optimally).\$\endgroup\$
– YakkJun 19 '15 at 13:14

What you are trying to create in a sand box is player agency. My definition of this is:

Players making informed decisions that have reasonable consequences

It is important to remember that there is an inherent information imbalance in RPG: you have it, they don't. It is your job as DM to give them information that is relevant, reasonable and accessible.

They key here is accessible. How do the players access information? They ask; but they have to know that they can ask. It seems that they don't know this. That's OK - tell them they can.

In the specific situation, ask them to recap the plan and tell them that they are allowed to ask you specific questions about the enemy camp. You can even prompt, e.g. "Do you want to know how many guards there are?" When they say yes (who wouldn't) you can say e.g. "You don't know, you would have to scout the camp." Your prompts should not all be relevant, throw in some red-herrings and incomplete information. Don't necessarily tell them what they want to know; tell them how they can find out.

As suggested in the comments: What information did you give the players to allow them to detect the spy? If you did not give them at least the idea that espionage on them could be a thing then you are being unfair. If this were a (modern) military operation security would be a prime consideration in the planning ... but your players are playing a game; they are not actually trained soldiers/security experts.

I am assuming the spy is an NPC and he is not the only NPC involved. It would be perfectly acceptable for the commanding general to open the meeting by introducing everyone - this is where you can drop the clues that the spy is different; newly arrived, speaks with an accent, whatever.

If and when the TPK occurs, the player's need to be able to see the long line of signs, bad decisions and ignoring of information that was actually given to them. If the TPK is 90% stupidity, 10% luck then that is agency.

\$\begingroup\$I'd also ask whether they were given the opportunity to detect the presence of the spy. If they were and failed then fair enough. However, if not then that is incredibly unfair on the players, as it gave them no chance of altering the situation\$\endgroup\$
– WibbsJun 16 '15 at 7:19

18

\$\begingroup\$I have a half-finished answer that's twice as long and half as clear; +1, most definitely. ... though, mine did have a character named "Clang de la Full Plate"... :(\$\endgroup\$
– minnmassJun 16 '15 at 7:19

3

\$\begingroup\$If I could tag more than one answer as accepted, I would accept this one as well. It gives a great explanation of why to save them.\$\endgroup\$
– Tim CJun 17 '15 at 7:23

Let them fail - miserably! But don't kill them...

A lot of good stories start out like this: You have a bunch of over confident wanna-be heroes who want to kill the evil general with a stupid plan. So of course it is doomed to fail, they will never kill them and they will surely get caught. But why should they all be killed?

The evil general probably has some use for them, he knows their plan, their motives and weaknesses. Maybe he can catch them and blackmail them into working for him. Or he can sell them as slaves. Or he can manipulate them - misdirect them into killing one of his enemies, while they think they are working against him! They are the perfect resource: A bunch of skilled and highly motivated naive warriors, which don't know they will do his dirty work, so if he manipulates them into killing someone important, he can deny all ties to them.

Another possibility would be a third party. Maybe the evil general has a right hand man, who wants the top for himself. The spy reports to him and he sees his chance to stage a coup d'etat - so Mr.RightHand stages the whole thing, has to build everything so their idiotic plan can indeed succeed in killing the general. Then they will succeed, but can become highly suspicious that everything magically works out, as if someone was helping them. And when they kill the general and flee - and hear that an even more evil manipulating bastard is now at the top, they will realize that they just played the puppets for Mr.RightHand - and are on the run from the whole army looking for the assassins.

\$\begingroup\$+1 for making all decisions - and failures - interesting! This situation also closely resembles Star Wars - "oh no, Jedi want to take me down, whatever shall I do...zap...aaaaand now I'm emperor." If someone is smart enough to run an entire army and be so important they ought to be smart enough to realize wanna-be assassins can be used for something better than lining ditches - and if they aren't then someone smarter must be really running the show.\$\endgroup\$
– BrianHJun 16 '15 at 13:57

9

\$\begingroup\$+1 This is a great answer, particularly the Evil Lieutenant option.\$\endgroup\$
– TaejangJun 16 '15 at 17:40

\$\begingroup\$-1 A lot of boring stories start out like this. It's, like, one of the most used clichés, especially in RPGs. Additionally, this doesn't take into account the "accessibility problem", as pointed out in other answers, and that would be the key. Sorry.\$\endgroup\$
– o0'.Jun 18 '15 at 8:26

1

\$\begingroup\$@Lohoris I don't think it is one of the most used cliches. Look at the accepted answer "spy changing alliance" this is cliche (hundreds of movies)! The convenient clue out of the sky, warning the party... never seen it before :-P You will always feed one cliche or the other, with almost any RPG-Story, the devil is in the details! How are the characters described, their backstory, motivations and details of the plot - that is what makes a story savory!\$\endgroup\$
– FalcoJun 18 '15 at 9:48

2

\$\begingroup\$And the question doesn't specify if there is an accessibility problem at all. You can equally likely run into the same situation with the player making informed bad decisions and running into their doom, despite the DM telling them 3 times "There could be something you overlooked wink" - and when that happens, rather than just closing the book "you are dead" - make an interesting story out of failure!!!\$\endgroup\$
– FalcoJun 18 '15 at 9:50

Let's simplify this scenario to what it amounts to: there's a button, and the players want to push it, and they're not sure what will happen, but you alone know that if they push it they die.

Right now, you only see the option that they die. It is inescapable that character death tends to suck. You could explain they had no way of finding out — that would be terrible. You could explain they could have found out, but they never asked the right questions (or figured out they needed to ask them), or they did ask the right questions but they failed their investigation roll. It's still going to suck. It's reasonable someone would respond with "What!? Why wouldn't you tell us something like that?" despite the circumstnaces. It could also produce unhappy memories to take away unless the players are prepared for this already and know full-well what's going to happen. It sounds like you don't particularly want that, and neither might your players.

So, here is the thing:

If I (...) simply portray the world as it is (they'll die.)

The solution is to not do that at this point, or rather, to reconsider what the world really is and what you could portray.

Nothing exists until it's been said.

This is an important lesson to learn as a GM who cares about their players driving the plot in a meaningful fashion. It's not something you'll always operate on depending on how hardcore you run your sandbox games, but it's a useful distinction to at least be aware of for cases like these difficult situations, because it puts extra tools in your kit.

To this point, a lot has been said and done at the table about the world. You also have some other stuff going on in your imagination about that world that's gone unsaid. That's useful.

One way of relating to that stuff in your imagination is that it exists as concretely as everything else expressed at the table. You've imagined it, it's done, it's happened. That's all well and good, and one of the standard modes of operation of a sandbox game.

As you're noticing, though, when you imagine an inevitable death-trap that you're not sure you want to engage in, it gets kind of unhelpful and constricting. On some level, a plan like the one you've created is basically world-level my guy syndrome: you don't really want to do it, it wouldn't be fun, but it's just what your world would do, so it's gotta happen, right? (No, not necessarily.)

The other option is this: the only parts of the world that exist are those that have been expressed at the table. Everything else doesn't exist. The stuff you came up with is just thoughts, doesn't matter, and is just a possibility in flux. Until you say it, it doesn't exist and never did. This isn't something you would apply always in a sandbox game, but in difficult situations, this can be your out.

Let's consider things from your players' perspective: They had a meeting, that happened. In your imagination, there was a spy. Does that really matter though? Does it make any difference to the players according to what they know if secretly various participants were changelings, or suits full of pixies, or the commander himself in disguise? Nothing says there was a spy there, except you in your conjuring a death trap based on nothing that was ever said. It won't make any difference to the players if the spy never existed. You're not committed to that path happening on your end, and you still have the freedom to change it.

Don't portray the world in your head, portray the world the players saw.

Your solution is to not portray the world according to the imaginary bits you came up with but never talked about in this scenario.

Consider the world at the table. Put aside everything you came up with privately as extraneous, be ready to trash it at a moment's notice. In writer's talk, be ready to kill your darlings. I run player-driven games, I make preparations based on where I think things will go, and I wind up trashing mostly everything by the end of the session because the players lead me in more interesting directions. My current GM does the same constantly. Right now, it's not so much your players have a plan that gets them all killed, it's that you have a plan that gets them killed, but it's one you have the opportunity to trash and replace with something more satisfying for everyone involved.

So, think about it from your players' perspective. Based on what they know, what would be a satisfactory way for the world's gears to turn?

Certainly, if they didn't plan well, it would be unsurprising if they have some measure of success but the plan nevertheless fails catastrophically. (For such shaky planning, for the plan to actually work might take freak accident.) Once the plan fails, the players could find themselves falling in deep intrigue. They might only escape at major cost. From their perspective this could be an exciting plot development, a lesson learned, and a fun game-changer (once they get over how badly their plan failed).

As opposed to the spy in the meeting, you could just as equally conjure that there was a spy on the roof who could only hear and see part of the plan, or that someone wandered by and listened in because they wanted pay-out for reporting what they could hear. You could even conjure up an opportunity for them to discover the spy before he or she could reveal all of the information, and let the players remove the spy from the equation somehow — murder, bribery, coersion, etc. All of this and more could leave the commander ready for an attempt on his life, but not so ready the players will walk into certain death.

Alternately, there may have been no spy, and the commander could genuinely be unprepared and killed — who knows where the plot will go from there. That would probably not be fully satisfying for both you and the players with such a hack-job plan. They have an adversary worth more than that.

However, if you have them walk into their own death because of all the imagination-crafting you did, that's as unsatisfying as the death button, or a response of "you walk into the hallway, but a big acid pit opens up and you all die. Whoops!"

Whose plan is this, really?

Do the characters have a plan that will get them killed? Or do your players have a plan that will get their characters killed?

There's a subtle difference, and your response should hinge on which of the two it is.

The players made a terrible plan

Players only have fairly limited information about the world and are often not as competent as the character they are playing. This can lead them to conclusions that are far off from those their characters would reach, because they are more intimately familiar with the world.

For example, a player might not know that spying is a big part of battle, or that armies commonly deploy forward scouts, or that troops without battle training are really likely to break under concentrated fire. He might come up with a plan that omits these unknown factoids and which might sound brilliant (or at least plausible) in his mind.

And if he tried to perform that plan, he would fail horribly because of this lack of knowledge. But the player is not leading the assault. His character is. And his character is Sir General Battleleader, the greatest military tactician in the kingdom. His character would never gloss over such details and make these rookie mistakes.

In this situation, the character is going to suffer because the player is playing someone more competent than he is. That's both going to create a really weird story ("This is the story of how the greatest general in the kingdom died like a rookie for no discernable reason.") and going to annoy the players (for the exact same reason)

If this is the situation you are in, part of the concept of a sandbox is that you, as the DM, volunteer information that the character would know but the player doesn't. Explain to the player that "you might not, but your character would know about A, B and C. Do you want to take that into account?"

Just like we generally don't allow players to use their own knowledge where the character should not have it ("Oh yeah, I totally read about this monster in the rulebook, there's a secret surrounding it, we can only beat it if we X.") we should allow players to have access to knowledge their characters should have but they don't, even if they don't ask. ("On the wall there is a symbol hidden amongst the words. Most people would never assume it to mean anything, but since you're a Lorekeeper you know it's an Arcane mark signifying X!")

After all; the player would never be able to deduce that there is any relevance to the symbol. He's not the Lorekeeper. But his character is, and if you wait for the player to ask "does this symbol mean anything?" before sharing it, you're making for a very strange story. The Lorekeeper would never miss the symbol. And the general would never fail to account for scouts and morale and all the stuff the players don't know much about.

The characters made a terrible plan

If the exact same plan was created not by Sir General Battleleader, but was instead concocted by the same players, only their characters where a group of inexperienced nobles with no formal military training, the response changes completely.

At this point, the pressure is on the players and not the DM to realise their characters are in over their heads. If they don't and think that they can make up for their characters' lack of experience with a brilliant plan... let them. It's a sandbox and you're basically exploring what happens when a bunch of incompetents with delusions of grandeur go up against a trained and experienced opponent. This is where a sandbox deviates from a novel and where the harsh reality sets in. Your characters are outmatched and outgunned and they are about to find out what that means.

But it'll be an enjoyable ride none-the-less as the players (and their characters) slowly start to realise that they're in over their heads and it's really their own fault.

In this situation, make sure to take notes as you're going along. Things like "If your character had any knowledge about military tactics, I would have told you X." If your players blame you for letting them get killed, use the notes to show them that you would have helped them if you could find any ingame justification, but you didn't see a reason why their characters would know and they never asked anyone with for help within the game.

A bit of both

"you should ask people to help you since you outmatched here" is a totally valid comment to give any character who would reasonably reach that conclusion. See the pointers in the first part. But if the character is played as arrogant or naive, it's also totally valid to drop that in the notes on "I would've mentioned it, but you wanted your character to be too proud to ask for help."

Usually, the best approach is somewhere in the middle, with you occasionally giving out things that the characters should know, and occasionally just giving the players the rope to hang their characters with since they are in over their heads and both the players and characters are oblivious to it.

\$\begingroup\$+1. Fully agree on the part about the characters being strong. Somewhat disagree with the part about the characters being weak. I think the main things is the strength of the characters leads the GM in the most natural direction for more fully communicating with the players. It seems to me that the bottom-line issue here is that the GM hasn't really communicated well enough with the players and OOC they have come up with a plan based on their lack of knowledge of the world.\$\endgroup\$
– WayneJun 18 '15 at 20:31

It is better to spoil surprises than to appear unfair. Do you best to ensure you have given them all the information they should have.

When things do go wrong, provide opportunities for retreat. While you know more than the players, you also know more than the NPCs. The NPCs aren’t perfect, and their countermeasures should have holes in them.

Having done 1 & 2, let things play-out, and do a post-mortem afterwards. Give the players an opportunity to consider what they did wrong and what they could’ve done differently. Listen to what wrong assumptions they may have made that can help you communicate better in the future. Discuss whether the group wants to adjust expectations. Are they still on-board with the sandbox nature of the game?

What you're looking for here is a lifeline for your players so they don't all get themselves brutally murdered. What you also know the players need is more information about their enemy, in the great tradition of unknown unknowns what the players don't know is the most dangerous thing about a sandbox, especially for players who are not used to such a gaming style.

For players new to sandboxes (Of which virtually all my games are these days) I have found what you need to do is present the end of multiple ropes through NPCs, information and environment whilst still giving the players ultimately the choice of what to do; as @Dale-m says, you need to create that agency. Those ropes tease about what information they can get if they pull them.

The players in your game situation have two critical issues

1) There is a spy who knows their plans.
2) They have no real information about the enemy army.

If they don't capture the spy and use their original plan they are heading for TPK (or capture) depending on how they roll it, this isn't a lot of fun. And fun is what we are about in RP games as far as I'm concerned.

So you need to inject an NPC, some information or a situation that indicates the problem, so, some examples in increasing order of "hey you have a problem"

Landlord/ commenting that the (spy name) left early and in a rush - investigation reveals they're heading towards the enemy army.

Veterans from an army that fought the players targets telling stories about the army

A turncoat from the enemy army reveals there is a spy who knows about an impending attack

When the players come up with a bad plan, I would look at their character sheets, and see if the bad plan is in character or not. I'd start by looking for relevant special talents. Any character who is supposedly a talented spy or tactician would detect any clear problems, and have a chance (I'd roll) to detect less obvious problems. I'd pass a note (or tell) these characters' players about these flaws. I'd also give similarly relevant feedback to characters with related skills (spy, tactics, strategy) or experience, or characters with high wisdom or intelligence or whatever (or even mediocre intelligence if I roll well enough for them). There should also be some chance, even if small, that they might get some clue that could lead them in the direction of the spy.

I wouldn't overdo the odds, but if the plan really stinks and the characters aren't incompetent, their players should get feedback from their characters' skills explaining what isn't great about their plans.

Also, if any of the characters have traits that aren't skills, but that make any plan something they would object to, I'd remind the player that their character wouldn't like (or would be terrified or morally outraged or whatever) about certain aspects of the plan.

If there are any NPCs involved who have talents or character to raise objections to a plan, I'd also roll for and then roleplay them.

This sort of feedback should be done all the time, and not just with disastrous plans, so it's not just an obvious meta-game alarm to the players when the GM stops and rolls all kinds of dice and passes notes when they plan something dangerous.

It's totally appropriate, though, for players used to easy/safe adventure stories and games, to explain to them what's foolish/dangerous about their plans, if the characters would know better. Safe adventure stories set up people to have no awareness of actual risks and precautions.

If they end up being caught anyway, especially if caught before they do much damage, the capable smart enemy may decide to do other things with them rather than kill them right away. This can be another great opportunity for interesting gameplay, roleplaying, and new experiences. If the players are high-status or otherwise talented or valuable, the target villain may want to ransom them or use their talents or knowledge, and/or learn all about who put them up to trying to kill him. The target may reveal some information that casts their original allegiance in doubt, or he may imprison them, sell them to slavers, hold some of them hostage, take away some or all of any fancy gear/magic/items they have, interrogate them directly or subtly, offer them tough offers of deals/threats, etc. Adventure stories and films offer many ideas for this - they're always capturing heroes leading to new adventures, not just killing them off immediately.

You don't need to change the world, you just need to change the outcome.

Depending on your players just letting them all die might be a valuable lesson. For many groups though that would not go down well, so a better approach is to give them advance warning that their plan is flawed through in-game agency.

In fact you have the perfect case here. There was a spy in the meeting. Great. Have him be caught!

Have allies of the players drag him in front of him and say they caught him sending messages to the general. Now the players know that he's warned of their plan. If they still go ahead then it's their own fault when they all die horribly...

\$\begingroup\$This seems a surprisingly good answer. Weaken the situation by letting the players know they've been found out.\$\endgroup\$
– JoshuaJun 16 '15 at 15:59

\$\begingroup\$If the players making a bad plan has the effect of making them catching the spy, you've added a weird effect to your sandbox, though, especially if you continue to have miracles save your players from themselves.\$\endgroup\$
– DronzJun 17 '15 at 15:49

1

\$\begingroup\$@dronz they didn't catch the spy, their friends did. A true sandbox world has multiple npc agencies as well as player vs enemy ones. Doing this once or twice as they get used to the world is fine. I would not suggest doing it all the time though.\$\endgroup\$
– Tim BJun 17 '15 at 15:55

\$\begingroup\$@TimB Ok, but I'd look for more natural solutions first. If I'd started the scenario with a competent enemy spy, rolled and he didn't get caught, I'd look to more natural ways to save the PCs from their players' dumb plan first, such as their friends pointing it out to them, or the PC's skills / intelligence giving them clues their plan is dumb. That way the situation isn't bent to accommodate player foolishness.\$\endgroup\$
– DronzJun 17 '15 at 15:59

Capture them alive, rather than killing them. The assassination fails, but the target has a reason to want to keep the PCs around. They wake up in prison. Of course, the daily logistics of prison life does not make for a very fun RPG, so you need to offer the PCs some opportunities to get out.

The simplest option is to just have their captor use them in a prisoner-exchange deal. All you have to do then is timeskip to the point where the PCs are released in neutral or even friendly territory, and some enemies of their boss, once imprisoned, are now free. The boss will be relieved to have them back, but not very happy with what had to be done to secure that. This is probably the most realistic option (short of killing them), but it's not one that I see used very often, because players can find it unsatisfying. Still better than killing them all, though.

A more common option, and one that lets both you and the players flex some gaming muscle, is to stage a jailbreak: weaknesses in prison security offer the PCs some opportunities to plan an escape and, eventually, execute one. Prisons tend to make good dungeons (in D&D settings, they often literally are dungeons), so you get to run the PCs in a few sessions where they don't have their normal gear and the place is crawling with hostiles. Do be nice and find a way to give (most of) their gear back at some point, though; perhaps they find it in a storage room. Of course, that storage room might be located much closer to the exit than to their cells...

If you're more into roleplay-heavier options, then you can have the target offer the PCs their freedom in exchange for service. "Ahem; now that I have your attention, I have a proposition for you", and so on. The PCs have to decide whether to take the deal or figure another way out of this mess. If they do take the deal, they're going to have a lot of explaining to do to their old boss, if they even have the opportunity to go back. If they don't, then you can fall back on the other options, but you've still gotten some good RP in. Either way, you win.

The bottom line is that when the enemy is intelligent, there are usually ways out of a TPK. It can mean giving the PCs just a bit of plot-protection, but it keeps the game going in ways that still preserve some sense of verisimilitude.

It sounds like your players are inexperienced with sandboxing. Instead of letting them march to their deaths, divert them.

A terrible rain comes up, and a nearby river goes out of its banks. The Evil General moves his camp a half-mile to higher ground. "Well, if you can start your plan, but first you'll have to wade 200' through mud up to your hips while wearing armor. What's plan B?"

It sounds like your players didn't know to ask questions, scout the enemy, etc. So divert them with some other task. Make it a training task. That is, you train them on how to play this kind of game. Find something more pressing, interesting, or lucrative than assaulting a camp of heavily armed men. As you walk towards the gate, you hear, then see, a well-dressed man in the town square. He's running back and forth grabbing people, and asking for help. He's loudly lamenting that bandit raiders have kidnapped his family! (If they ask around, they'll find he's known in the town to be a trader of exotic goods...) Instead of setting them up to attack a camp of heavily armored and motivated mercenaries and killers, what if it were a 'camp' of kobolds with really short attention spans. Now when they approach the camp, An arrow flies by Bob's head. It looks like it came from a little person with a bow that's in a tree about 30' to your left. The person is yelling something. If they hem and haw, start planning and discussing, shooting arrows back, or otherwise waste time... You notice a noise from the camp. You see small persons running around. Some are putting on armor. They're making tons of noise." The party knows they are spotted and they see the inattentive 'bandit raiders' start forming up. They choose to run. The kobolds don't follow too far. The next day, the scenario resets and they can try again. It will not take too long before them to start looking for ways to dispatch the sentry or avoid him entirely. Then they'll find the next problem with their non-plan... Once they save the merchant's family by defeating the Kobold warlord (and more importantly, flee from the first 10 hare-brained failures) they'll have a better idea on how to proceed with their original task. As they near the Evil General's camp... Ahead of you, there is a pair of soldiers lounging under a tree by the road. Two horses horses are nearby. One of the soldiers has a bugle. They aren't looking at you. They ought to figure it out then. Further, this will be a good training experience for you, too, if you aren't experienced running one of these games.

I was observing a D&D game where the party walked into a dungeon they found. They were met by a well-prepared wizard who was 8 or more levels above them. The TPK was quick, efficient, and otherwise exactly what you'd expect if this were real life. The players were furious about being slaughtered. The GM simply said, "You should have not gone in there" and "Why is it that players think they have the right to live?" Does that sound fun? Don't be That Guy.

Remember, you are playing a game - you may be trying to make it "realistic", but that doesn't mean it has to be completely true to life! So, there's a simple solution to your problem: Let the players die. Then resurrect them.

Maybe they make it to the banks of the styx, where they are met by [god of the dead] who offers to bring them back to life if they will [task]. Or they approach the gates of heaven and an angel says "Sorry, you've still got a destiny - back to earth with you!"

If you're willing to lost a bit of the realism, you could even have them continue playing in the afterlife, something that is far from unheard of, in fantasy games at least.

Ok, I have a short answer with what I would do, based on my experience as a DM.

I would have the general throw a lot of force at the weakest part of the plan, capturing/killing that one PC. I would have him use enough force that the other PCs can't be pursued too hard without sacrificing the defense of the general.

This way you send the message to the player "don't do stupid sh*t" but also avoid a TPK. They pay for their terrible plan with a life, but the party and campaign go on.

You could also have them roll an intelligence check first and if they pass, they realize either a) there could be a spy, or b) their plan is silly since they have no information about whether it would work.

It depends. If your campaign dies with the characters then you have to insert an element that changes what happens, or shows them the consequences of their actions (a seer, a dream etc). Otherwise let them get killed and start over. TPK is the term, total party kill. If it is their decision, and they know the risks, and you are not victimising them or being overly nasty and it makes sense, let them do it would be my advice.

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